A recent analysis shows that some state child restraint laws, such as those in Arizona, Michigan, and South Dakota, covered children only up until the age of four during the studied period. View an interactive map of child restraint laws in all 50 states. (Credit: sean dreilinger/Flickr)

Child restraint laws across many states have gaps that could leave kids vulnerable to vehicle-crash injuries, a new study reports.

The findings show that many child restraint laws lag behind existing research on vehicular safety and fail to follow guidelines adopted by medical experts.

[related]

In the US, nearly 250,000 children are injured every year in car crashes and approximately 2,000 die from their injuries. Moreover, the child passenger fatality rate in the US is at least double that of other comparable wealthy nations.

Previous studies have shown that the proper use and placement of child restraint devices can reduce the injuries and fatalities.

For the new study, published in the journal Social Science and Medicine,researchers at New York University and Temple University examined child passenger safety laws from 1978 to 2010 in all 50 states, analyzing changes over time and inter-state differences.

The results show that some state child restraint laws, such as those in Arizona, Michigan, and South Dakota, cover children only up until the age of four during the studied period.

The American Association of Pediatrics recommends the use of child restraint devices until the vehicle seat belt fits them properly, which is typically when they have reached 4 feet 9 inches in height and are between 8 and 12 years of age.

Lack of clarity

In other cases, existing laws are not clear, creating the possibility for confusion.

For instance, even when states have laws covering children of older ages, many of them fail to distinguish child passengers in need of rear-facing infant seats from those that should use forward-facing car safety seats (CSS) or booster seats.

In 2010, only 12 states explicitly required the use of booster seats while nine mandated infant seats and six required forward-facing CSS.

The researchers also point to the high number of exemptions that state laws grant. For instance, as of 2010, 33 states failed to protect child passengers if the drivers are driving commercial passenger vehicles.

As of 2010, 16 states exempted drivers that carry more children than their vehicle space can handle—as long as the drivers used restraint devices for as many children as the space allowed.

National laws for alcohol

The legal terrain for child restraint laws differs sharply from that for state alcohol laws—and in the study, researchers suggest that federal incentives may explain the difference.

The number of states with 21-year minimum legal drinking age (MLDA) increased from 17 in 1984 to all 50 in 1988—four years after Congress passed the National MLDA Act conditioning states’ enactment of such law to the continued full provision of the highway funds.

Similarly, the number of states with the law limiting the legal blood alcohol concentration to 0.08 percent increased from 19 states in 2000 to all 50 in 2006—six years after Congress passed an act tying each state’s enactment of such laws to the continued provision of federal highway funds.

The report includes an interactive map of child restraint laws in all 50 states.

The research was supported by grants from the National Institute on Alcohol Abuse and Alcoholism, part of the National Institutes of Health, and the Robert Wood Johnson Foundation’s Public Health Law Research Program (PHLR).